Predicate transformer semantics were introduced by Dijkstra in his seminal paper "Guarded commands, nondeterminacy and formal derivation of programs". They define the semantics of an imperative programming paradigm by assigning to each statement in this language a corresponding predicate transformer: a total function between two predicates on the state space of the statement. In this sense, predicate transformer semantics are a kind of denotational semantics. Actually, in Guarded commands, Dijkstra uses only one kind of predicate transformers: the well-known weakest preconditions (see below).
Moreover, predicate transformer semantics are a reformulation of Floyd–Hoare logic. Whereas Hoare logic is presented as a deductive system, predicate transformer semantics (either by weakest-preconditions or by strongest-postconditions see below) are complete strategies to build valid deductions of Hoare logic. In other words, they provide an effective algorithm to reduce the problem of verifying a Hoare triple to the problem of proving a first-order formula. Technically, predicate transformer semantics perform a kind of symbolic execution of statements into predicates: execution runs backward in the case of weakest-preconditions, or runs forward in the case of strongest-postconditions.

The first part is devoted into a thorough review of the D'Hondt-Panangaden
approach to quantum Predicate transformer semantics where quantum
predicates are treated as observables with their eigenvalues within the unit
interval.

(iii) There exist predicate transformers that do not distribute over conjunctions. ...
language in Section 10.2 this isomorphism is shown to be respected by the
relational total correctness semantics _|_ and the Predicate transformer semantics wp; ...

This means that we have altogether three different semantics for statements: an (
operational) game semantics, a (backward) Predicate transformer semantics, and
a (forward) choice semantics. We show that these semantics are consistent with ...

Maximum Expressive Power with Minimal Construction
December 19, 2009 in GrammarWare, MaintenanceWare, ModelWare, Other Methodologies
In this story we start from the known definition for Expressive power to extend its scope to semantics programming languages, which have numerous ways to express the specific meanings (below 8 formalismis are listed) of tems of languages. We suggest that (near) all of these semantic principles can be combined in the atomistic semantics, which is a novel hybrid construction, a high-abstraction way to simulate source code.

Contest linkBLeh , why did they have to make today's warmup the 14:00 GMT one instead of last one? I had an exam during the warmup and it seems I didn't have time to solve or even open the interesting parts of the problem set. The examSo, at 10:00 AM GMT-4 (exactly the same time as the warm up's start time) I was supposed to solve an exam.